Advances in medical technology are enabling doctors to identify and treat injuries that went unnoticed 20 years ago. For example, physicians can now use miniaturized television cameras to see inside a joint. With this tool, they have been able to identify and treat a shoulder injury called a glenoid labrum tear.
The shoulder joint has three bones: the shoulder blade (scapula), the collarbone (clavicle), and the upper arm bone (humerus). The head of the upper arm bone (humeral head) rests in a shallow socket in the shoulder blade called the glenoid. The head of the upper arm bone is usually much larger than the socket, and a soft fibrous tissue rim called the labrum surrounds the socket to help stabilize the joint. The rim deepens the socket by up to 50% so that the head of the upper arm bone fits better. In addition, it serves as an attachment site for several ligaments.
Injuries to the tissue rim surrounding the shoulder socket can occur from acute trauma or repetitive shoulder motion. Examples of traumatic injury include:
- Falling on an outstretched arm
- A direct blow to the shoulder
- A sudden pull, such as when trying to lift a heavy object
- A violent overhead reach, such as when trying to stop a fall or slide
- Shoulder dislocation or subluxation
Throwing athletes or weightlifters can experience glenoid labrum tears as a result of repetitive shoulder motion.